The main purpose of establishing the “Źródliskowe Zbocza” nature reserve was to protect the local landscape and unique flora. The eastern and western slopes form the tunnel valley of Lake Długie, and are covered with a unique type of forest - the blackcurrant alder forest, where the lower forest layers include blackcurrant shrubs. The undergrowth is also home to typical headwater vegetation, including large bitter-cress, moss and liverworts. The local fauna, which includes birds, mammals, reptiles and amphibians, is mostly under protection.